Package structure module of bump posited type lead frame

ABSTRACT

A package structure that uses a bump posited type lead frame is disclosed. The package structure uses a lead frame having holes thereon for accommodating conductive bumps of a chip or a positioning film having openings thereon for accommodating conductive bumps of a chip or both to avoid the flow and deformation of the conductive bumps during bonding so as to prevent the electrical property of the package structure from degradation and increase the reliability of the chip package.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lead frame package structure, andmore particularly to a package structure module of bump posited typelead frame.

2. Description of the Related Art

Owing to the demands and availability of electronic products withmultifunction as well as the development of semiconductor technology,the package technologies of advanced commercial semiconductor devicesmust advance toward simplified processes, minimized structure size, highintegration, strengthened electrical connection and high thermalconductivity from conventional package processes, large-size structureand limited electrical characteristics. For lead frame packagetechnologies, conventional lead frame packages which bond a chip havingbumps onto a lead frame with pre-plated silver thereon to completeelectrical connection and to form a flip chip package structure haveseveral drawbacks. For example, positioning and bonding of the bumpsonto the lead frame usually lack accuracy so that the electricalconnection and package reliability are degraded and the yield ratio isalso decreased. Moreover, even the positioning of the bumps dose notcause any bonding issue, due to the wettability and fluidity of thebumps, the bumps still could be bonded onto the lead frame inaccuratelyso as to result in the degradation of electrical property of the packagestructure.

In view of the drawbacks mentioned with the prior art, there is acontinued need to develop new and improved package structure thatovercomes the disadvantages associated with prior art. The requirementsof this invention are that it solves the problems mentioned above.

BRIEF SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a packagestructure with pre-etched holes formed on leads of a lead frame used asbump positioning and bonding to avoid the degradation of electricalproperty resulting from the dislocations of chip bumps and increase thereliability of the chip package.

It is another object of this invention to provide a package structurewith a positioning film on a lead frame used as bump positioning toavoid the degradation of electrical property resulting from thedislocation of chip bumps and increase the reliability and life time ofthe chip package.

It is a further object of this invention to provide a package structurewith pre-etched holes formed on leads of a lead frame and a positioningfilm on the lead frame used as bump positioning and bonding to avoid thedegradation of electrical property resulting from the dislocations ofchip bumps and increase the reliability and life time of the chippackage.

To achieve these objects, and in accordance with the purpose of theinvention, the invention provides a package structure comprising a chiphaving conductive bumps and a lead frame having holes thereon foraccommodating the conductive bumps, the chip bonds to the lead frame viathe conductive bumps.

In one embodiment of the invention, the package structure comprises achip having conductive bumps and a lead frame, and a positioning film onthe lead frame, the chip bonds to the lead frame via the conductivebumps, the positioning film having openings for accommodating theconductive bumps.

In another embodiment of the invention, the package structure comprisesa chip having conductive bumps, a lead frame having holes thereon foraccommodating the conductive bumps and a positioning film on the leadframe, the chip bonds to the lead frame via the conductive bumps, thepositioning film have openings for accommodating the conductive bumps,each the opening is superimposed on each the hole.

The invention also provides a lead frame module of a package structurecomprising a lead frame comprising leads having holes thereon foraccommodating conductive bumps of a chip and a positioning film on thelead frame, the chip bonds to the lead frame via the conductive bumps;the positioning film have openings for accommodating the conductivebumps, each the opening is superimposed on each the hole.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is best understood by reference to the followingdetailed description when read in conjunction with the accompanyingdrawings.

FIG. 1 shows a top view of a package structure;

FIG. 2A shows a bottom view of the first embodiment of the packagestructure;

FIG. 2B shows a cross sectional view of the first embodiment of thepackage structure of the invention;

FIG. 3A shows a bottom view of the second embodiment of the packagestructure;

FIG. 3B shows a cross sectional view of the second embodiment of thepackage structure of the invention;

FIG. 4A shows a view of the third embodiment of the package structure;

FIG. 4B shows a cross sectional view of the third embodiment of thepackage structure of the invention;

FIG. 5A shows a top view of a corner of the lead frame corresponding tothe first and second embodiment of the invention; and

FIG. 5B and 5C show a top view and a cross sectional view of only onelead having one hole thereon respectively.

Common reference numerals are used throughout the drawings and detaileddescription to indicate like elements.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a top view of a package structure 100 is shown. Inthis top view of the package structure 100, a protecting dielectricmaterial 101 and a chip 102 are shown. The protecting dielectricmaterial 101 comprises a molding compound, but other dielectric materialcan also be used. Based on the package structure 100 shown in FIGS. 1,three embodiments of the package structure of the invention are shown inFIGS. 2A–2B, 3A–3B and 4A–4B.

Referring to FIG. 2A, a bottom view of the first embodiment of thepackage structure 100 is shown. In this bottom view of the packagestructure 100, a lead frame 103 and a positioning film 104 as well asthe protecting dielectric material 101 are shown. The lead frame 103comprises leads 105 and a die attach pad 106. FIG. 2B shows a crosssectional view of the first embodiment of the package structure of theinvention. Particularly, FIG. 2B shows a cross sectional view of theleft portion of the package structure 100 shown in FIG. 1 and FIG. 2A.In this embodiment, the chip 102 bonds onto the lead frame 103 viaconductive bumps 108. The leads of the lead frame 103 have holes 110 forpositing the bumps 108. The number and location of the holes 110 on thelead frame 103 depend on the number and position of the bumps 108 of thechip 102. For example, each hole 110 can be formed on each lead 105. Thepositioning film 104 also has openings superimposed on the hole 110 andthe openings are used to fix the bumps 108 so as to prevent the bumps108 from deformation. The protecting dielectric material 101 is formedbetween the chip 102 and the lead frame 103. The holes 110 of the leadframe 103 and the openings of the positioning film 104 are used to avoidthe flow and deformation of the bumps 108 during bonding so as toprevent the electrical property from degradation and increase thereliability of the chip package.

Referring to FIG. 3A, a bottom view of the second embodiment of thepackage structure 100 is shown. In this bottom view of the packagestructure 100, the lead frame 103 and the protecting dielectric material101 are shown. The lead frame 103 comprises leads 105 and the die attachpad 106. FIG. 3B shows a cross sectional view of the second embodimentof the package structure of the invention. FIG. 3B particularly shows across sectional view of the left portion of the package structure 100shown in FIG. 1 and FIG. 3A. In this embodiment, the chip 102 bonds ontothe lead frame 103 via conductive bumps 108. The leads of the lead frame103 have holes 110 for positing the bumps 108. The number and locationof the holes 110 on the lead frame 103 depend on the number and positionof the bumps 108 of the chip 102. For example, each hole 110 can beformed on each lead 105. The protecting dielectric material 101 isformed between the chip 102 and the lead frame 103. The holes 110 of thelead frame 103 are used to avoid the flow and deformation of the bumps108 during bonding so as to prevent the electrical property fromdegradation and increase the reliability of the chip package.

Referring to FIG. 4A, a view of the third embodiment of the packagestructure 100 is shown. In this view of the package structure 100, thelead frame 103 and the positioning film 104 are shown while the chip 102and the protecting dielectric material 101 are not shown. The lead frame103 comprises leads 105 and the die attach pad 106. FIG. 4B shows across sectional view of the third embodiment of the package structure ofthe invention. Particularly, FIG. 4B shows a cross sectional view of theleft portion of the package structure 100 shown in FIG. 1 and FIG. 4A.In this embodiment, the chip 102 bonds onto the lead frame 103 viaconductive bumps 108. The positioning film 104 has openings superimposedon the lead frame 103 and the openings are used to fix the bumps 108 soas to prevent the bumps 108 from deformation. The number and location ofthe openings on the positioning film 104 depend on the number andposition of the bumps 108 of the chip 102. The protecting dielectricmaterial 101 is formed between the chip 102 and the lead frame 103. Theopenings of the positioning film 104 are used to avoid the flow anddeformation of the bumps 108 during bonding so as to prevent theelectrical property from degradation and increase the reliability of thechip package.

Referring to FIG. 5A, a top view of a corner of the lead frame 103corresponding to the first and second embodiment of the invention isshown. As shown in FIG. 5A, each hole 110 is formed on each lead 105.FIG. 5B and 5C show a top view and a cross sectional view of only onelead 105 having one hole 110 thereon respectively.

This disclosure provides exemplary embodiments of the present invention.The scope of the present invention is not limited by these exemplaryembodiments. Numerous variations, whether explicitly provided for by thespecification or implied by the specification, such as variations instructure, dimension, type of material and manufacturing process may beimplemented by one of skill in the art in view of this disclosure.

1. A package structure comprising: a chip having conductive bumps; and a lead frame having a die attach pad, leads and holes on said leads for accommodating said conductive bumps, said chip bonds to said lead frame via said conductive bumps.
 2. The package structure according to claim 1 further comprising a protecting dielectric material.
 3. The package structure according to claim 2, wherein said protecting dielectric material comprises a molding compound.
 4. A package structure comprising: a chip having conductive bumps; a lead frame having a die attach pad and leads, said chip bonds to said lead frame via said conductive bumps; and a positioning film on said lead frame, said positioning film having openings for accommodating said conductive bumps, said openings are superimposed on said leads.
 5. The package structure according to claim 4 further comprising a protecting dielectric material.
 6. The package structure according to claim 5, wherein said protecting dielectric material comprises a molding compound.
 7. A package structure comprising: a chip having conductive bumps; a lead frame having a die attach pad, leads and holes on said leads for accommodating said conductive bumps, said chip bonds to said lead frame via said conductive bumps; and a positioning film on said lead frame, said positioning film have openings for accommodating said conductive bumps, each said opening is superimposed on each said hole.
 8. The package structure according to claim 7 further comprising a protecting dielectric material.
 9. The package structure according to claim 8, wherein said protecting dielectric material comprises a molding compound.
 10. A lead frame module of a package structure comprising: a lead frame comprising leads having holes thereon for accommodating conductive bumps of a chip, said chip bonds to the lead frame via said conductive bumps; and a positioning film on said lead frame, said positioning film have openings for accommodating said conductive bumps, each said opening is superimposed on each said hole. 